Water displacing oil relative permeability time varying rule representation method based on ternary dynamic parameters

Abstract

The invention discloses a water displacing oil relative permeability time varying rule representation method based on ternary dynamic parameters. The water displacing oil relative permeability time varying rule representation method comprises the following steps: a stable production stage is divided; the stage is subjected to progressively-decreasing analysis; an endpoint value and a shape of a relative permeability curve are determined; the relationship between the saturability of residual oil and the accumulated water displacing intensity under different instantaneous water displacing intensity is regressed; the relationship between the water phase relative permeability and the instantaneous water displacing intensity under the residual oil is regressed; the relationship between an oil phase index m and the accumulated water displacing intensity, the relationship between the oil phase index m and the instantaneous water displacing intensity, the relationship between a water phase index n and the accumulated water displacing intensity, as well as the relationship between the water phase index n and the instantaneous water displacing intensity are regressed; and a ternary dynamic parameter water displacing oil relative permeability time varying rule representation general formula based on the effective wetting phase saturability, the accumulated water displacing intensity and the instantaneous water displacing intensity is obtained in a simultaneous mode. Through actual production effect inspection, it is proved that through the water displacing oil relative permeability time varying rule representation method, the development history fitting precision of medium and high seepage water displacing sandstone oil reservoirs and the residual oil saturability distribution prediction precision can be improved significantly, thus the prediction accuracy of a production dynamic indicator change trend is improved, and high universality is achieved.

Description

technical field [0001] The invention relates to a technique for characterizing the time-varying law of the water-displacement oil phase-permeability curve of a medium-high-permeability water-displacement sandstone reservoir in oil and gas exploration and development technology. Background technique [0002] Under the condition of water flooding, the pore structure and wettability of the reservoir change greatly, so the water flooding efficiency and the relative permeability curve of water flooding oil are not static. However, the current characterization methods are mostly limited to considering the influence of cumulative water flooding intensity or instantaneous water flooding intensity on the relative permeability curve alone, and it is difficult to consider the dynamic change law of the water flooding oil phase permeability curve by both cumulative water flooding intensity and instantaneous water flooding intensity. Comprehensive characterization of the impact cannot pre...

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Problems solved by technology

[0003] However, the traditional characterization method has the following inherent defects: (1) The cores used in laboratory tests may not necessarily represent the actual variation of seepage characteristics underground; (2) Only the endpoint values ​​of relative permeability curves and cumulative water flooding intensity or instantaneous water flooding intensity can be established. The factors considered are not comprehensive enough, and the influence of cumulative water flooding intensity and instantaneous water flooding intensity on the shape change of relative permeability curve cannot be considered; (3) The change law of relative permeability curve obtained by regression analysis of similar sedimentary unit relative permeability curve Large limitations, difficult to promote the use of

The above defects lead to low prediction accuracy of remaining oil saturation distribution, which cannot accurately guide development and adjustment

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